textproduct: Quad Cities

KEY MESSAGES

- Extreme Heat Warning continues through Friday evening for areas along/south of an Ottumwa, IA to Galesburg, IL line from the prolonged hot and very humid conditions. The humid conditions will continue into the holiday weekend, but cloud cover and rounds of thunderstorms make for great uncertainty if there will be the need for additional heat headlines.

- With the storm track edging closer in from the west/northwest, the local area will be more susceptible to occasional rounds of thunderstorms into the Holiday weekend. Strong to severe storms will be possible, as well as locally heavy rainfall.

SHORT TERM /THROUGH FRIDAY/

Issued at 204 PM CDT Thu Jul 2 2026

The heat headlines have been extended until 10 PM Friday for areas along and south of an Ottumwa, IA to Galesburg, IL line. It will be another very warm night for this area. Although heat indices Friday may only around 100, heat affects are cumulative and this would be day five for this area.

The outflow boundary from the nocturnal storms across Wisconsin has stalled from roughly a KALO to KDKB line and is now slowly moving north. Storms have initiated along this line and will likely be confined to this area through late afternoon. However, the 18z sounding has a very weak cap and minimal inhibition. Thus a few rogue isolated storms cannot be fully ruled out through sunset along and south of Highway 30.

There is a respectable upper level disturbance moving east northeast out of eastern Nebraska which will likely initiate new storms in central Iowa this afternoon. These storms will grow upscale overnight into an organized storm complex that will generally move east northeast as a weak LLJ develops.

Corfidi vectors become perpendicular to each other suggesting the potential for slow storm movement and for storms to repeat over the same areas. Given the very high moisture levels in the atmosphere, heavy rain is a given.

The HREF and REFS probability matched means are painting a fairly large area of northeast Iowa with 2+ inches of rain. The HREF LPMM is even more disturbing suggesting smaller areas of 4+ inches.

If the storm complex tonight would latch onto the outflow boundary then rainfall would have a high probability of being excessive. Due this possibility, a flood watch has been issued for the Highway 20 corridor from Dubuque on west.

Most storms overnight should remain below severe limits. However, localized severe downbursts due to precipitation loading in the downdrafts cannot be ruled out.

Outflow boundaries from the nocturnal convection will push south across the area and help initiate additional convection. Areas along and north of the I-80 corridor have the better chances for rain.

Friday will be yet another humid day. However, clouds and residual convection should keep heat indices in the 95 to 100 range for the northern two thirds of the area. Boundaries from the overnight convection should initiate new diurnal convection across the entire area, especially the south third during the afternoon.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Issued at 245 AM CDT Thu Jul 2 2026

Friday night through Sunday

Model ensembles and mid to upper jet progs(which generally do well at this range) show the continued southeast upper ridge de- amplify to allow flattened progressive flow to press acrs the upper Midwest into Saturday. This flow embedded with short waves and MCVs means the adjustment of the main storm track from the north half of the plains through the GRT LKS and on into the northeast CONUS. This will open up the local area for more direct hits by storm clusters through at least early Sunday. The oppressive humidity will still be here(aided by crop evapo- transpiration) through the weekend, but convective debris and outflow between the episodes of storms should help reduce the need for additional heat headlines. A damaging wind producing MCS may move acrs IA and then effect the local area later Friday night into early Sat morning. Besides an almost daily chance for strong to severe storms through at least Saturday, swaths of heavy rainfall may really add up through Sunday especially acrs the northwest half of IA, southern MN, and into WI.

Longer range progs and upper jet patterns suggest a good bout of ridging to unfold acrs the upper Midwest for a reprieve from the storms by early next week. Temps may be more seasonable and not as hot early next week as well.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1222 PM CDT Thu Jul 2 2026

Outflow boundary from the WI convection runs from about KALO to KDKB. Isolated convection has initiated along it and will likely persist through the afternoon. More convection will initiate after 21z/03 across northeast Iowa and grow upscale into another TSRA complex overnight. Probability of IFR impacts is better than 50 percent for KDBQ. Outflow boundaries from the storm complex will be the foci for isolated to scattered convection across eastern Iowa and northern Illinois after 12z/03.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Flood Watch through Friday morning for IAZ040>042. Extreme Heat Warning until 10 PM CDT this evening for IAZ063>068-076>078. Extreme Heat Warning until 10 PM CDT Friday for IAZ087>089-098- 099. IL...Extreme Heat Warning until 10 PM CDT this evening for ILZ009- 015>018-024. Extreme Heat Warning until 10 PM CDT Friday for ILZ025-026-034- 035. MO...Extreme Heat Warning until 10 PM CDT Friday for MOZ009-010.